Self-contained airbag system

ABSTRACT

A side impact airbag system for a vehicle including a system housing defining an interior space and arranged on a side of the vehicle alongside at least a portion of a passenger compartment of the vehicle. One or more airbags are arranged in the interior space of the system housing such that when inflating, the airbag(s) is/are expelled from the system housing into the passenger compartment. An inflator is arranged at least partially within the interior space of the system housing for inflating the airbag(s). A crash sensor, preferably an electronic crash sensor, initiates inflation of the airbag(s) via the inflator upon a determination of a crash requiring inflation of the airbag(s). The crash sensor includes a sensor housing arranged within and/or proximate to the system housing, and a sensing mass arranged in the sensor housing to move relative to the sensor housing in response to accelerations of the sensor housing resulting from the crash into the first side of the vehicle. Upon movement of the sensing mass in excess of a threshold value, the crash sensor initiates the inflator means to inflate the airbag(s).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S: patent applicationSer. No. 08/101,017 filed Sep. 16, 1993 now U.S. Pat. No. 5,842,716.

FILED OF THE INVENTION

This invention relates to self-contained airbag systems and moreparticularly to self-contained side impact airbag systems.

BACKGROUND OF THE INVENTION

Self-contained airbag systems contain all of the parts of the airbagsystem within a single package, in the case of mechanicalimplementations, and in the case of electrical or electronic systems,all parts except the primary source of electrical power and, in somecases, the diagnostic system. This includes the sensor, inflator andairbag. Potentially these systems have significant cost and reliabilityadvantages over conventional systems where the sensor(s), diagnostic andbackup power supply are mounted separate from the airbag module. Inmechanical implementations in particular, all of the wiring, thediagnostic system and backup power supply are eliminated. In spite ofthese advantages, self-contained airbag systems have only achievedlimited acceptance for frontal impacts and have so far not beenconsidered for side impacts.

The “all-mechanical” self-contained systems were the first to appear onthe market for frontal impacts but have not been widely adoptedpartially due to their sensitivity to accelerations in the vertical andlateral directions. These cross-axis accelerations have been shown toseriously degrade the performance of the most common all mechanicaldesign that is disclosed in Thuen, U.S. Pat. No. 4;580, 810. Bothfrontal and side impact crashes frequently have severe cross-axisaccelerations.

Additionally, all-mechanical self contained airbag systems, such asdisclosed in the Thuen patent, require that the sensor be placed insideof the inflator which increases the strength requirements of theinflator walls and thus increases the size and weight of the system. Onesolution to this problem appears in Breed, U.S. Pat. No. 4,711,466, buthas not been implemented. This patent discloses a method of initiatingan inflator through the use of a percussion primer in combination with astab primer and the placement of the sensor outside of the inflator. Onedisadvantage of this system is that a hole must still be placed in theinflator wall to accommodate the percussion primer that has its ownhousing. This hole weakens the wall of the inflator and also provides apotential path for gas to escape.

Another disadvantage in the Thuen system that makes it unusable for sideimpacts, is that the arming system is sealed from the environment by anO-ring. This sealing method may perform satisfactorily when the moduleis mounted in the protected passenger compartment but it would not besatisfactory for side impact cases where the module would be mounted inthe vehicle door where it can be subjected to water, salt, dirt, andother harsh environments.

Self-contained electrical systems have also not been widely used. Whenairbags are used for both the driver and the passenger, self-containedairbag systems require a separate sensor and diagnostic for each module.In contrast to mechanical systems the electronic sensor and diagnosticsystems used by most vehicle manufactures are expensive. Thisduplication and associated cost required for electrical systemseliminates most of the advantages of the self contained system.

Sensors located in the passenger compartment of a vehicle can catch mostairbag-required crashes for frontal impacts, particularly if theoccupants are wearing seatbelts. However, researchers now believe thatthere are a significant number of crashes which cannot be sensed in timein the passenger compartment and that this will require the addition ofanother sensor mounted in the crash zone (see, for example, Breed, D.S., Sanders, W. T. and Castelli, V. “A Critique of Single PointSensing”, Society of Automotive Engineers Paper No. 920124). If true,this will eventually eliminate the use of self-contained airbag systemsfor frontal impacts.

Some of these problems do not apply to side impacts mainly because sideimpact sensors must trigger in a very few milliseconds when there is nosignificant signal at any point in the vehicle except where the car iscrushing or location rigidly attached to this crush zone. Each airbagsystem must be mounted in the crush zone and generally will have its ownsensor. Self contained airbag systems have heretofore not been used foroccupant protection for side impacts which is largely due to themisconception that side impact sensing requires the use of elongatedswitches as is discussed in detail in U.S. Pat. No. 5,231,253,incorporated by reference herein. These elongated prior art side impactcrush-sensing switches are not readily adaptable to the more compactself-contained designs. The realization that a moving mass sensor wasthe proper method for sensing side impacts has now led to thedevelopment of the side impact self contained airbag system of thisinvention. The theory of sensing side impacts is included in the '253patent referenced above.

In electromechanical and electronic self-contained modules, the backuppower supply and diagnostic system are frequently mounted apart from theairbag system. If a wire is severed during a crash but before the airbagdeploys, the system may lose its power and fail to deploy. This is morelikely to happen in a side impact where the wires must travel inside ofthe door. For this reason, mechanical self-contained systems have asignificant reliability advantage over conventional electrical systems.

Finally, the space available for the mounting of airbag systems in thedoors of vehicles is frequently severely limited making it desirablethat the airbag module be as small as possible. Conventional gasgenerators use sodium azide as the gas generating propellant. Thisrequires that the gas be cooled and extensively filtered to remove thesodium oxide, a toxic product of combustion. This is because the gas inexhausted into the passenger compartment where it can burn an occupantand is inhaled. If the gas is not permitted to enter the passengercompartment; the temperature of the gas can be higher and the productsof combustion can contained toxic chemicals, such as carbon dioxide.

These and other problems associated with self contained airbag systemsare solved by the invention disclosed herein.

OBJECTS AND SUMMARY OF THE INVENTION

This invention is primarily concerned with a novel self-contained airbagsystem for protecting occupants in side impacts. This is accomplished byusing the sensors described in U.S. Pat. No. 5,231,253 referenced above,along with other improvements described in detail below. This inventionis secondarily concerned with applying some of the features of the novelside impact system to solving some of the problems of prior art allmechanical airbag systems discussed above.

The sensitivity to cross axis accelerations of current all mechanicalairbag systems, for example, is solved in the present invention, asdiscussed in U.S. Pat. No. 5,233,141, incorporated by reference herein,through the substitution of a hinged sensing element for the ballsensing mass in the Thuen patent.

The problems resulting from the hole in the inflator wall when apercussion primer is used as in Breed, U.S. Pat. No. 4,711,466, aresolved in the present invention through the placement of sensitivepyrotechnic material in a cavity adjacent to the outside wall of theinflator and then using shock from a stab primer to initiate thepyrotechnic material and thus the inflator. An alternate solution, asdiscussed below, is to make the size of the hole created in the inflatorby the action of the stab primer small so that the total quantity of gaswhich escapes into the sensor is small compared with the quantity of gasused to inflate the airbag.

Finally, in the self-contained airbag system disclosed herein, provisionis made to exhaust the gas outside of the passenger compartment, intothe vehicle doors, or other side areas of the vehicle. This permits theuse of higher gas temperatures and alternate propellant formulations,such as nitro-cellulose, which produce toxic combustion products. Bothof these changes reduce the size, weight and cost of the system.

Briefly, the self-contained airbag system of this invention consists ofa sensor having a movable sensing mass, means to sense the position ofthe sensing mass to determine if the airbag should be deployed, a sealedhousing, a gas generator for producing the gas to inflate the airbag, anairbag, and mounting hardware.

The principal objects and advantages of this invention are:

-   -   1. To provide a self contained side impact occupant protection        airbag system incorporating the advantages of a movable mass        sensor resulting in a low cost, compact airbag system.    -   2. To provide a frontal impact all mechanical airbag system        incorporating a hinged sensing mass to eliminate the effects of        cross-axis acceleration on the operation of the sensor.    -   3. To provide a method of minimizing the leakage of the inflator        gases out of the inflator portion of a self contained airbag        system into the sensor portion and the associated problems.    -   4. To provide a side impact airbag system which utilizes the        crush of the vehicle side to arm the sensor and motion of a        sensing mass to initiate deployment.    -   5. To provide a method of hermetically sealing a self contained        airbag system while permitting an external force to be used to        arm the system.    -   6. To provide a more compact self contained side impact airbag        system by providing for the exhausting of the airbag gas into        the vehicle door or side, therefore permitting the use of higher        temperature gas and propellants which would otherwise not be        viable due to their toxic products.    -   7. To provide an all-mechanical airbag system utilizing a        cantilevered firing pin spring which also provide the biasing        force on the sensing mass thereby providing a simplified design.    -   8. To provide an all-mechanical airbag system with a thin sensor        mounted outside of the inflator housing but in line with it to        reduce the size of the system and permit the use of conventional        inflator designs.    -   9. To provide a highly reliable side impact occupant protection        electromechanical self-contained airbag system.    -   10. To provide a highly reliable side impact occupant protection        electronic self contained airbag system.    -   11. To provide a method of obtaining the power for an electrical        self contained airbag system from other components within the        door thereby minimizing the requirement for separate wiring for        the airbag system.    -   12. To provide a power supply within the self contained module        and a simplified diagnostic system for an electrical self        contained airbag system.    -   13. To provide a self contained airbag system design that        permits the arming of the sensor after it has been mounted onto        the vehicle but before the inflator is mounted to provide        greater safety against unwanted deployments.

Other objects and advantages will become apparent from the discussionbelow.

In one embodiment of a side impact airbag system for a vehicle, theairbag system comprises a system housing defining an interior space andarranged on the first side of the vehicle alongside at least a portionof a passenger compartment of the vehicle, one or more inflatableairbags arranged in the interior space of the system housing such thatwhen inflating, the airbag(s) is/are expelled from the system housinginto the passenger compartment, and inflator means arranged at leastpartially within the interior space of the system housing for inflatingthe airbag(s). The inflator means comprise an inflator housingcontaining propellant. The airbag system also includes a crash sensorfor initiating inflation of the airbag(s) via the inflator means upon adetermination of a crash requiring inflation thereof The crash sensorcomprises a sensor housing arranged within the system housing, proximatethereto and/or mounted thereon, and a sensing mass arranged in thesensor housing to move relative to the sensor housing in response toaccelerations of the sensor housing resulting from the crash into thefirst side of the vehicle. Upon movement of the sensing mass in excessof a threshold value, the crash sensor initiates the inflator means toinflate the airbag(s). The threshold value may be the maximum motion ofthe sensing mass required to determine that a crash requiring deploymentof the airbag(s) is taking place.

The crash sensor may be an electronic sensor and the movement of thesensing mass is monitored. The electronic sensor generates a signalrepresentative of the movement of the sensing mass that may be monitoredand recorded over time. The electronic sensor may also include amicroprocessor and an algorithm for determining whether the movementover time of the sensing mass as processed by the algorithm results in acalculated value that is in excess of the threshold value based on thesignal.

In some embodiments, the crash sensor also includes an accelerometer,the sensing mass constituting part of the accelerometer. For example,the sensing mass may be a micro-machined acceleration sensing mass inwhich case, the electronic sensor includes a micro-processor fordetermining whether the movement of the sensing mass over time resultsin an algorithmic determined value which is in excess of the thresholdvalue based on the signal. In the alternative, the accelerometerincludes a piezo-electric element for generating a signal representativeof the movement of the sensing mass, in which case, the electronicsensor includes a micro-processor for determining whether the movementof the sensing mass over time results in an algorithmic determined valuewhich is in excess of the threshold value based on the signal.

The inflator means may be any component or combination of componentswhich is designed to inflate an airbag, preferably by directing gas intoan interior of the airbag. One embodiment of the inflator means maycomprise a primer. In this case, the crash sensor includes an electroniccircuit including the accelerometer and the primer such that uponmovement over time of the sensing mass results in a calculated value inexcess of the threshold value, the electronic circuit is completedthereby causing ignition of the primer.

The system housing may comprise a mounting plate having a bottom walland flanged side walls, the bottom wall having an aperture, whereby theinflator housing is arranged in the aperture. The system housing may bearranged inside a door of the vehicle or between inner and outer panelsnot associated with a door of the vehicle.

The airbag system may also include a capacitor arrange within the systemhousing to supply power to initiated deployment of the airbag system andan electronic diagnostic system arranged within the system housing topermit diagnoses of a fault within the airbag system.

Another embodiment of an airbag safety restraint system for a vehicleincluding an electronic crash sensor comprises an inflatable airbaghaving an interior, and an inflator assembly having an inflator housing,an ignitable gas generating material contained in the inflator housingand at least one passage extending between the gas generating materialand the interior of the airbag such that upon ignition of the gasgenerating material, gas is generated and flows through the at least onepassage into the interior of the airbag to inflate the airbag. Theelectronic crash sensor causes ignition of the gas generating materialupon a determination of a crash requiring inflation of the airbag andcomprises a sensor housing, a sensing mass arranged in the sensorhousing to move relative to the sensor housing in response toaccelerations of the sensor housing resulting from the crash whereby asignal representative of the movement of the sensing mass is generated,and a micro-processor comprising an algorithm for determining whetherthe movement of the sensing mass over time results in a calculated valuewhich is in excess of a threshold value based on the signal. If themovement over time of the sensing mass results in a calculated valuethat is in excess of the threshold value, the micro-processor causesignition of gas generating material and thus inflation of the airbag.

The sensor housing may be mounted proximate to the inflator housing. Thecrash sensor may include an accelerometer whereby the sensing massconstitutes part thereof, e.g., a micro-machined element, or theaccelerometer may include a piezo-electric element. The inflatorassembly may include a primer for igniting the gas generating materialwhereby the crash sensor includes an electronic circuit including theaccelerometer and the primer such that upon movement of the sensing massover time resulting in a calculated value in excess of the thresholdvalue, the electronic circuit is completed thereby causing ignition ofthe primer.

Yet another embodiment of an airbag safety restraint system for avehicle including an electronic crash sensor comprises, in addition tothe inflatable airbag and inflator assembly described immediately above,a sensor housing, and an accelerometer arranged in the sensor housingand including a sensing mass movable relative to the sensor housing inresponse to accelerations of the sensor housing resulting from thecrash. The accelerometer is arranged to generate a signal representativeof the movement of the sensing mass over time. The crash sensor isarranged to cause ignition of the gas generating material if themovement over time of the sensing mass represented by the signal resultsin a calculated value that is in excess of a threshold value. The sensorhousing may mounted proximate to or directly on the inflator housing.The sensing mass may be a micro-machined element. The accelerometer mayalso include a piezo-electric clement for generating the signal. Inanother basic embodiment of the side impact airbag system in accordancewith the invention, the system includes a system housing defining aninterior space and which is arranged on the side of the vehiclealongside at least a portion of a passenger compartment of the vehicle,a sensor housing, a sensing mass arranged in the senor housing to moverelative to the sensor housing in response to accelerations of thesensor housing in excess of a predetermined threshold value resultingfrom impact into the first side of the vehicle, one or more inflatableairbags arranged in the interior space of the system housing such thatwhen inflating, the airbag(s) is/are expelled from the system housinginto the passenger compartment, and inflator means arranged at leastpartially within the interior space for inflating the airbag(s). Theinflator means comprise an inflator housing containing propellant andthe sensor housing is coupled to the inflator housing. The system alsoincludes initiation means arranged in the sensor housing responsive tothe movement of the sensing mass upon acceleration of the sensor housingfor initiating the inflator means to inflate the airbag(s) and expel thesame from the system housing into the passenger compartment.

The system housing may comprise a mounting plate having a bottom walland flanged side walls, the bottom wall having an aperture in which theinflator housing is arranged. The inflator housing may include a firstflanged housing section and a second housing section, the first housingsection being arranged in the aperture such that a flanged portion ofthe first housing section abuts against the bottom wall, the sensorhousing is connected to the first housing section. The sensor housingmay comprise a top cover adapted to be situated most proximate anexterior of the vehicle and opposed wall portions cooperating to definea sealed interior space whereby the sensing mass is arranged in theinterior space of the sensor housing. The initiation means may comprisea biasing spring arranged in the interior space of the sensor housingand releasably restrained by the sensing mass and a firing pin arrangedin connection with the biasing spring.

In some embodiments, the sensor housing further comprises a bottom coverhaving an orifice arranged such that when the biasing spring is releasedfrom the sensing mass upon acceleration of the sensor housing, thefiring pin passes through the orifice. In this case, the inflator meansfurther comprise a stab primer located in the inflator housing adjacentthe orifice and in a position to be impacted by the firing pin.

In the alternative, the stab primer is arranged in the interior space ofthe sensor housing in a position to be impacted by the firing pin whenthe biasing spring is released from the sensing mass upon accelerationof the sensor housing whereby initiation of the stab primer creates ashock which is transmitted through the sensor housing to the inflatorassembly. The inflator assembly includes a shock sensitive pyrotechnicmix that ignites upon impact by the shock created upon initiation of thestab primer. The sensor housing thus may comprises a solid bottom coverarranged alongside the inflator housing.

The sensing mass may be pivotally coupled to the sensor housing toenable the mass to pivot about a vertical axis in response toaccelerations of the sensor housing in excess of the predeterminedthreshold value resulting from impact into the side of the vehicle. Thesensing mass may be substantially planar and square. The sensing massmay be arranged in the sensor housing for movement relative to thesensor housing only in response to accelerations of the sensor housingcaused by the impact into the side of the vehicle.

Sealing means may be provided for hermetically sealing the sensorhousing to prevent passage of moisture and contaminants into or out ofthe sensor housing. In one embodiment, the sealing means comprise amember cooperating at least with the inflator housing to surround thesensor housing within a closed, hermetically sealed compartment. Whenthe inflator housing has first and second housing sections, the membermay comprise a tubular section surrounding the first housing section ofthe inflator housing and a spherical section sealing an end of thetubular section and being situated over the sensor housing.

The sensor housing may comprise a side wall, a hinge for pivotallyattaching the sensing mass to the side wall, and a releasable firing pinrestrained by the mass. The inflator means are initiated by movement ofthe firing pin. The system housing is mounted such that upon a sideimpact causing acceleration of the sensor housing in excess of thepredetermined threshold value, the sensing mass pivots about the hingecausing release of the firing pin, and thus initiating the inflatormeans to inflate the airbag(s). This sensing mass may also becantilevered where the attachment to the wall performs the function of ahinge as in certain micro-machined accelerometer designs.

In some embodiments, crush detecting means are provided for preventingmovement of the sensing mass in response to accelerations of the sensorhousing in excess of the predetermined threshold value resulting fromimpact into the first side of the vehicle until crush of the first sideof the vehicle is detected. Thus, the sensor will actuate only uponcrush of the vehicle and a sufficient velocity change. The crushdetecting means comprise a sensor can surrounding the senor housing andincluding an outer cover and a tubular wall defined an interior space inwhich the sensor housing is situated. The crush detecting means may alsoinclude a spherical pusher member adapted to receive a force from theouter cover upon crush of the first side of the vehicle, a first leveradapted to be pushed by the pusher member and hingedly mounted at oneend thereof to the sensor housing to enable it to rotate about anattachment point to the sensor housing, and a second lever hingedlyconnected at a first end to the first lever and pivotally connected tothe sensor housing. The second lever has a second end extending throughan aperture in a wall of the sensor housing and restraining the sensingmass from movement whereby rotation of the second lever causes thesecond end of the second lever to pull out of the sensor housing.

The vehicle may include a pusher plate arranged in a side door on thefirst side of the vehicle whereby the system housing is arrangedalongside at least a portion of the pusher plate.

In certain embodiments, the initiation means comprise a first electricalspring contract biased against the sensing mass and a second electricalcontact arranged on the top cover of the sensor housing whereby uponmovement of the sensing mass, the first contact is caused to engage thesecond contact and complete an electrical circuit.

As to mounting of the system housing, the system housing is mounted suchthat the sensor housing is usually closer to an exterior of the side ofthe vehicle than the inflator housing and thus more forwardly in a sideimpact crash direction than the inflator housing. The system housing maybe arranged inside a door of the vehicle or between inner and outerpanels of a section other than the door of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the followingnon-limiting drawings in which:

FIG. 1 is a perspective view with certain parts removed of an allmechanical self contained airbag system for mounting on the side of avehicle to protect occupants in side impacts;

FIG. 2 is a cross sectional view of the apparatus of FIG. 1 taken alongline 2-2;

FIG. 3 is an enlarged fragmentary view of the sensing mass and attachedlever arm extending from the D-shaft prior to rotation of the sensingmass incident to a crash as adapted to the all mechanic system of U.S.Pat. No. 4,580, 810;

FIG. 4 is a similar view of FIG. 3 showing the sensing mass rotated as aresult of a crash;

FIG. 5 is a view of the apparatus shown in FIG. 4 taken along line 5-5and rotated 90 degrees to the right;

FIG. 6 is a cross section view of a sensor for use in an all mechanicalsystem where the sensor is mounted outside of the inflator housing,shown in an unarmed or safe position prior to assembly with an inflator;

FIG. 7 is a cross section view of the sensor of FIG. 6 shown mounted onan inflator, shown in a fragmentary view, after it has triggered inresponse to a vehicle crash;

FIG. 8 is a cross section view of a through bulkhead initiation systemadapted to a mechanical self contained airbag system;

FIG. 9 is a perspective view of a mechanical self contained airbagsystem using a crush sensing arming system, shown in the state before acrash occurs;

FIG. 9A is a blowup with certain parts removed showing a portion of thesensor shown in FIG. 9 in the unarmed position;

FIG. 10 is a cross section view of the apparatus of FIG. 9 taken alongline 10-10 showing the crush sensing arming system after it has beenactivated by vehicle crush but before the sensing mass of thediscriminating sensor has begun to move;

FIG. 10A is a blowup with certain parts removed showing a portion of thesensor shown in FIG. 10 in the armed position;

FIG. 11 is a cross section view of the apparatus of FIG. 9, also takenalong line 10-10, showing the crush sensing arming system after it hasbeen activated by vehicle crush and showing the sensing mass of thediscriminating sensor after it has moved and released the firing pin,triggering the inflation of the airbag;

FIG. 11A is a blowup with certain parts removed showing portion of thesensor shown in FIG. 11 in the fired position;

FIG. 12 is a perspective view of a side impact airbag systemillustrating the placement of the airbag vents in the door panel and theexhausting of the inflator gases into the vehicle door and also showingthe use of a pusher plate to adjust for the mismatch between the pointof impact of an intruding vehicle and the sensor of a self containedside impact airbag system;

FIG. 13 is a cross section view of a self contained side impact airbagsystem using an electro-mechanical sensor;

FIG. 14 is a cross section view of a self contained side impact airbagsystem using an electronic sensor;

FIG. 15 is a schematic of the electric circuit of an electromechanicalor electronic self contained side impact airbag system; and

FIG. 16 is a side view of a vehicle showing the preferred mounting oftwo self contained airbag modules into the size of a coupe vehicle, oneinside of the door for the driver and the other between the inner andouter side panels for the rear seat passenger.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the accompanying drawings wherein like reference numeralsrefer to the same or similar elements, FIGS. 1 and 2 show anall-mechanical self-contained airbag system for mounting on the side ofa vehicle to protect occupants in side impacts in accordance with theinvention which is designated generally as 100. The airbag system 100contains one or more inflatable airbags 110, an inflator assembly 120, amounting plate 160 for mounting the airbag system 100 on the side of thevehicle and a sensor assembly 140 mounted to the inflator assembly 120.The sensor assembly 140 contains a rotatable, substantially planarsensing mass 141 and a cantilevered biasing spring 142 which performsthe dual purposes of biasing the sensing mass 141 toward its at restposition shown in FIG. 2 and also providing the energy to the firing pin143 required to initiate a stab primer 122 as further described below.The sensing mass 141 contains a firing pin spring-retaining portion 144that restrains the firing pin 143 during the sensing time and releasesit when the sensing mass 141 has rotated through the sensing angle. Theretaining portion 144 is an L-shaped descending part formed on a planarsurface of the sensing mass 141 and defines a cavity for retaining anend of the spring 142.

As shown in FIG. 1, the mounting plate 160 constitutes a housing for theairbag system 100, i.e., it has a bottom wall and flanged side wallsextending from edges of the bottom wall which define an interior spacein which the airbag(s) 110 and a portion of the inflator assembly 120are arranged. The bottom wall is substantially flat and has asubstantially circular aperture. The inflator assembly 120 is positionedin the aperture so that a portion thereof extends on either side of thebottom wall (See FIG. 2). Also as shown in FIG. 2, the housing of theinflator assembly 120 includes a flange that abuts against the bottomwall of mounting plate 160 around the aperture. As will be appreciatedby those skilled in the art, the flanged side walls of the mountingplate 160 are positioned around a panel on the side of the vehicle,e.g., a blow-out panel in the side door, so that the airbag(s) 110 wheninflating will be expelled from the interior space defined by themounting plate 160 into the passenger compartment of the vehicle. Themounting plate 160 may thus be mounted to a frame of the side door byattaching a flanged side walls to the frame or attaching another portionof the mounting plate to the frame. The actual manner in which themounting plate 160 is mounted in the side door, or on the side of thevehicle, is not critical so long as the mounting plate 160 is positionedto allow the airbag(s) 110 to be expelled from the interior space intothe passenger compartment. Mounted as such, the sensor assembly 140 willbe most proximate the exterior of the vehicle with the airbag 110 mostproximate the passenger compartment of the vehicle.

The sensing mass 141 is connected to the housing 101 of sensor assembly140 through a hinge 145 at one end whereby the opposed end isunrestrained so that the sensing mass 141 rotates about the hinge 145.In view of the mounting of the airbag system 100 on the side of thevehicle, hinge 145 defines a rotation axis which is perpendicular to thelongitudinal direction of travel of the vehicle (x) as well asperpendicular to a direction (y) transverse to the longitudinaldirection of travel of the vehicle, i.e., it is a vertical axis (z).

The sensor housing 101 includes opposed housing wall portions 146 and148, a top cover 150 and a bottom cover 151 which is connected to,mounted on or the same part as a top cover 121 of the inflator assembly120. The sensor housing 101 is filled with air and sealed (whenappropriately mounted to the inflator assembly 120 whereby a smallorifice 127 in bottom cover 151 is closed by the inflator assembly 120)so to maintain a constant air density regardless of the ambienttemperature or pressure. The sensor housing walls 146,148 and sensingmass 141 are preferably molded along with the hinge 145 in a singleinsert molding operation to provide a careful control of the dimensionsof the parts and particularly of a clearance 152 between the walls146,148 and the sensing mass 141 for the reasons described below.

The inflator assembly 120 comprises a stab primer 122, igniter mix 130associated with the stab primmer 122, one or more propellant chambers123 containing propellant 124 and a series of cooling and filteringscreens 125. In the particular design shown in FIGS. 1 and 2, the stabprimer 122 has been placed inside of an igniter housing portion 126 ofthe housing of the inflator assembly 120, the housing of the inflatorassembly being formed by opposed housing sections 121 and 129. Housingsections 121 and 129 cooperate to define a substantially cylindricalhousing for the inflator assembly 120. Housing section 121 is coupled tothe sensor housing 101. Exit orifices 128 are provided in the housingsection 129 to allow the gas generated by the burning propellant 124 toflow into the airbag 110 to inflate the same. A small orifice 127 hasbeen left open in the bottom cover 151 of the housing 101 of the sensorassembly 140, as well as the housing section 121, to allow the firingpoint 143 to enter into the interior of the inflator assembly 120 andcause initiation of the stab primer 122. The stab primer 122 is from afamily of the most sensitive stab primers requiring less than 25 in-ozof energy for activation. The standard M55 military detonator is amember of this class and has been manufactured in very large quantitiesduring war time. For the purposes of this disclosure, the term primerwill be used to represent body primers and detonators. The small orifice127 will permit some gas to enter the sensor housing 101 during the timethat the propellant 124 is burning and inflating the airbag 110 butsince its area is less than 1% of the area of the exit orifices 128through which the generated gas enters the airbag 110, less than 5% ofthe generated gas will pass into the sensor. Naturally, a larger orificecould be used but in all cases the amount of gas which passes into thesensor housing 101 will be less than 10% of the total gas generated.Since this gas will be hot, however, it will destroy the sensor assembly140 and leak into the door. In another implementation discussed below, athrough bulkhead initiation system is used to prevent any gas frompassing into the sensor assembly from the inflator assembly.

During operation of the device, sensing mass 141 rotates relative tosensor housing 101 in the direction of the arrow (shown in FIG. 2) underthe influence of the acceleration with its motion being retarded by thebiasing spring 142 and the gas pressure forces. Upon a sufficientrotation, biasing spring 142 is released from the retaining portion 144of the sensing mass 141 and moves toward the inflator assembly 120 andthe firing pin 143 formed in connection with the biasing spring 142moves to impact stab primer 122 which burns and ignites the igniter mix130. The igniter mix, which is typically composed of boron and potassiumnitrate, then ignites the propellant 124 that burns and generates gas.The gas then flows through exit orifices 128 into the inflatable bag110, inflating the bag.

In the embodiment shown in FIGS. 1 and 2, the stab primer 122 has beenlocated in the center of the inflator housing. This is the conventionallocation for electrical primers in most driver's side inflator designs.The sensor is placed adjacent and in line with the inflator permittingthe use of conventional inflator designs which minimize the size,complexity and weight of the inflator. The sensing mass 141 isapproximately of square shape and the sensor housing 101 is madecircular to mate with the inflator design.

In the particular design shown in FIGS. 1 and 2, a burning propellantinflator design was illustrated. Naturally, other propellanttechnologies such as a stored gas or hybrid (a combination of stored gasand propellant) could have been used without departing from theteachings of this invention.

It will be appreciated by those skilled in the art that since the airbagsystem 100 is designed to activate in side impacts, the sensing mass 141is arranged for movement in a direction perpendicular to the sides ofthe vehicle, i.e., perpendicular to the longitudinal direction of travelof the vehicle, or in a pivoting movement about a vertical pivot axis.In this manner, the acceleration of the sensor housing 101 inward intothe passenger compartment resulting from a crash into the side of thevehicle, will cause the sensing mass 141 to move or pivot outward towardthe impacting object thereby releasing its hold on the biasing spring142.

FIG. 3 shows a fragmentary view of a sensing mass 341 and an attachedlever arm 356 extending from a D-shaft 358 prior to rotation of thesensing mass incident to a crash as adapted to the all-mechanical systemof Thuen, U.S. Pat. No. 4,580,810. This figure corresponds to FIG. 6 ofthe Thuen. patent and shows the improved sensing mass design. FIG. 4shows the same view as FIG. 3 with the sensing mass rotated, under thetorque from spring 360 acting on ball 470, into the actuating positionwhere it has released the firing pin. to initiate deployment of theairbag. FIG. 4 corresponds to FIG. 7 in the '810 patent. FIG. 5 is aview taken along line 5-5 of FIG. 4 and shows the shape of the sensingmass 341. Sensing mass 341 is retained in sensor housing 338, by cover339, and rotates with D-shaft 358. This rotation is facilitated bypivots 371, which form part of the D-shaft, and pivot plates 370. Inthis manner, the sensing mass 341 is hinged to the sensor housing 338permitting only rotational motion and rendering the sensor insensitiveto the effects of cross-axis accelerations. In this embodiment, sensingmass 341, lever arm 356, ball 470, pin 469 and the D-shaft 358 are allmade as one part that reduces the cost of the assembly. Naturally, theycould be made as separate parts and assembled. When D-shaft 358 rotatesthrough a sufficient angle, it releases firing pin 336 in the samemanner as shown in FIGS. 8 and 9 of the '810 patent. The motion of thesensing mass 341 is undamped since the clearance between the sensingmass 341 and sensor housing 338 is sufficiently large so as to minimizethe flow resistance of the air as the mass rotates. Naturally, inanother implantation, the mass could be redesigned to have its motiondamped by the flow of a gas in the manner shown in FIGS. 1 and 2 above.Also, two sensor systems of the type disclosed in FIGS. 3-5 can be usedin the all-mechanical system in a similar way as showing in the '810patent.

The all-mechanical system as depicted in FIGS. 3-5 requires that aspecial inflator be designed to accommodate the sensor within itshousing. There has already been a substantial investment in tooling andproduction facilities for electrically actuated inflators by severalinflator manufactures. Also, substantial reliability statistics havebeen accumulated on these inflator designs through the hundreds ofmillions of miles that airbag equipped vehicles have traveled. It isdesirable to build on this base with new systems that can be done usingthe sensor designs of this invention as depicted in FIGS. 6 and 7. Thissensor design is adapted to be attached to a standard electricalinflator design where a stab primer 691 is used in place of theelectrically actuated squib normally used.

The sensor-initiator is shown generally as 600 in FIG. 6. In a similarmanner as described above, sensing mass 641 rotates in sensor housing630 during a crash against the force provided by a cantilevered biasingspring 662 until a D-shaft 658 has rotated sufficiently to release afiring pin 636. Once released, firing pin 636 is propelled by firing pinspring 635 and impacts primer 691 to initiate deployment of the airbag.A washer containing an orifice 692 is provided in the top of primer 691to minimize the leakage of inflator gases from the inflator 690 whilethe propellant is burning (FIG. 7). In this manner, the sensor does nothave to be constructed of strong materials as discussed in the abovereferenced patent.

In one configuration of a self-contained system, the sensor assembly andthe airbag and inflator assembly are kept separate until mounted ontothe vehicle. In this case, the sensor is mounted using an appropriateapparatus (not shown) to the steering wheel after the wheel is mountedto the vehicle. Then, the airbag module is assembled to the steeringwheel. In this case, the sensor is armed after it has been installedonto the vehicle through the use of arming screw 670. The inflator isonly brought into contact with the sensor after the sensor has beenmounted on the vehicle, thus minimizing the chance of an inadvertentactuation prior to installation. To arm the sensor, arming screw 670 isrotated after the sensor is mounted onto the steering wheel causing itto move downward in its housing 674. This removes the retaining cylinder673 from blocking the motion of locking ball 675 that removes a lock onthe firing pin. As long as ball 675 remains locking the firing pin 636,rotation of the mass 641 will not releases the firing pin and the sensoris unarmed. Additional apparatus, not shown, can be used to prevent theassembly and disassembly of the sensor from the steering wheel unlessthe arming screw 670 is in the unarmed position. Also, interferencebetween the head 680 of the arming screw 670 and the surface 693 of theinflator 690 prevents assembly of the inflator and airbag module to thesteering wheel until the sensor has been armed. Thus, in this verysimple manner, an inexpensive all-mechanical airbag system can be madeusing standard inflator designs with minor modifications.

In FIGS. 1 and 2, the stab primer was shown as part of the inflatorassembly, i.e., contained within the housing of the inflator assemblydefined by housing portions 121,129. On the other hand, in FIG. 8 across section view of a through bulkhead initiation system adapted to amechanical self-contained airbag system is illustrated. In this case,the stab primer 822 is instead part of a sensor assembly 840, i.e.,arranged in the sensor housing on the bottom cover thereof if present,and when the stab primer 822 is initiated by a firing pin 842 formed inconjunction with a cantilevered, biasing spring (as in the embodimentshown in FIGS. 1 and 2), it creates a shock on one side of an inflatorhousing wall 821 which is transmitted through the wall and interactswith a shock sensitive pyrotechnic mix 829 which has been placed into acavity 805 in the igniter mix. Inflator housing wall 821 is alongsidethe bottom cover of the sensor housing, but in the alternative theinflator housing wall may be the same as the bottom cover of the sensorhousing. This through-bulkhead initiation system and the particularpyrotechnic mix formulation is well known to ordinance engineers whereit has been applied to military devices. Such a system has not beenused, however, in airbag systems. In this manner, a hole is not openedbetween the sensor assembly and the inflator assembly and the gas isprevented from leaking into the sensor assembly.

In FIG. 9, a perspective view of a mechanical self-contained airbagsystem using a crush sensing arming system designated generally at 950is shown in the state before a crash occurs. In this embodiment, thesensor is armed when the vehicle door skin, or side skin, is crushed towhere it impacts a curved impact plate, not shown, which then impacts asensor can 970 surrounding the sensor assembly and displaces an outercover 951 thereof relative to a sensor housing 901. Sensor can 970 has atubular wall arranged partially alongside a housing section of theinflator assembly to thereby define a closed space between the outercover 951 and an outer surface of the inflator assembly in which thesensor assembly is positioned. The sensor crush-sensing outer cover 951has a slight arcuate shape so that it oil-cans downward pressing onlever 971 through a semi-spherical pusher member 979. Lever 971 ishingedly mounted at one end thereof to enable it to rotate about itsattachment point 972 to the sensor housing 901 and causes lever 973 toalso rotate about its pivot point 974 on the sensor housing 901 byvirtue of hinge 978. An end 975 of lever 973 extends through an aperture904 in a wall of the sensor housing 901 and serves to restrain thesensing mass 941 from any movement (FIG. 10). The rotation of lever 973causes the end 975 of lever 973 to pull out of the sensor housing 901where it was detenting the sensing mass 941 and preventing the sensingmass 941 from rotating to the degree necessary to release a firing pinspring 942. The sensing mass 941 is then free to move and release thefiring pin spring 942 causing the firing pin spring 942 to ignite thestab primer in the inflator assembly, either by contact therewith or bypressure against the inflator assembly housing (see above) causinginflation of the airbag (FIG. 11A). Thus, until the sensor experiences acrushing force from the crash, the airbag system cannot deploy. Thesensing mass 941, firing pin spring 942, inflater assembly and airbagmay have the same structure as described above with reference to FIGS. 1and 2. Other features of any of the disclosed embodiments notinconsistent with the embodiments shown in FIGS. 9-11 may also beincorporated therein.

Levers 971 and 973 are joined together by hinge 978 and can be made froma single piece of material. In this case, the hinge would be formedeither by a coining or stamping operation or by a milling operation.Naturally, the two levers need not be joined together.

This provides a sensor system that requires the occurrence of twoenvironments that are always present in a crash, crush and velocitychange. The crush sensing outer cover 951 is designed to respond and armthe sensor when impacted from any reasonable direction by an impactplate (not shown) which is likely to occur in a crash. For manyvehicles, the crush may not reach the sensor at the time that deploymentis required. In the case where two systems are used on each side of thevehicle, for example, and an impact occurs at the A-pillar, the rearseat system may not experience crush in time. The arming system shown inFIG. 9 could still be used where the arming would occur when the systemis mounted onto the vehicle instead of when the crash occurs. In thiscase, the curved impact plate would not be necessary and the deflectionof the sensor cover would occur either during the mounting process or bya separate operation after the system is mounted.

FIG. 10 is a cross section view of the apparatus of FIG. 9 taken alonglines 10-10 showing the crush sensing outer cover 951 and lever systemafter end 975 has moved out of aperture 904 as a result of crush of thevehicle but before the sensing mass 941 of the discriminating sensor hasbegun to move. FIG. 11 is a similar view of the apparatus of FIG. 10 butshows the sensing mass 941 of the discriminating sensor after it hasmoved and released firing pin 942, triggering the inflation of theairbag.

The motion of the sensing mass 941 is damped by the requirement that airmust flow between the sensing mass and the housing in the mannerdescribed in more detail in the '253 patent referenced above. Naturally,other damping methods such as magnetic damping could also be used.

In the case of FIG. 9, the sensor is entirely surrounded by a metal can970 that is formed by a drawing process. The sensor can 970 is attachedto the inflator assembly, more particularly, the sensor can 970 isattached to one or more housing sections thereof, thereof. Theattachment of the sensor can 970 to the inflator assembly or housingsections(s) thereof is achieved using structural adhesive 990 such as aurethane or epoxy compound. In this manner, the sensor is hermeticallysealed.

The term hermetic seal as used herein means a seal which will not permitthe passage of any significant amount of moisture or other contaminantsinto the interior of the self-contained airbag module and further willnot permit the passage of gas into or out of the sensor housing ofsufficient quantity as to change th gas destiny by more than about 5% atany time over the life of the vehicle. Each vehicle manufacturer has aaccelerated life test that can be used along with appropriate sensortesting equipment to test the sensor seals according to this definition.Typical O-ring seals are not hermetic by this definition howeverproperly designed plastic and metal welded seals and epoxy and urethaneseals are hermetic.

FIG. 12 is a perspective view of a side impact airbag systemillustrating the placement of the airbag vents in the door panel and theexhausting of the inflator gases into the vehicle door 1200 and alsoshowing the use of a pusher plate 1201 to adjust for the mismatchbetween the point of impact of an intruding vehicle and the sensor of aself contained side impact airbag system 1220. The pusher plate 1201 isshown attached to the main structural door beam 1202 in thisillustration but other mounting systems are also possible. The airbagsystem 1220 is shown between the inner panel 1230 and the outer panel1240 of the door 1200 The pusher plate 1201 is dimensioned and installedin the door so that during a side impact to any portion of the side ofthe vehicle which is likely to cause intrusion into the passengercompartment and contact an occupant, the pusher plate will remain in asubstantially undistorted form unit it has impacted with the sensorcausing the sensor to begin deployment of the airbag. In thisimplementation, a non-sodium azide propellant, such as nitro-cellulose,is used and the gas is exhausted into the door though a pair of orifices1220. The airbag system 1220 may be any of those disclosed herein.

FIG. 13 is a cross section view of a self-contained side impact airbagsystem using an electromechanical sensor. An electromechanical senor isone in which the sensing is accomplished through the motion of a sensingmass from a first at-rest position to a second activating position atwhich point an event happens which typically involves the closing of aswitch by mechanical or magnetic means. In the embodiment shown in FIG.13, biasing spring contact 1301 is caused to engage contact 1302arranged on top cover 1350 when the sensor experiences a crash asdescribed above, i.e., acceleration of the sensor housing 1310 above apredetermined threshold value which results in movement of the sensingmass until the biasing contact 1301 contacts the other contact 1302.Specifically, the biasing spring contact 1301 is positioned in aposition (e.g., bearing against sensing mass 1341 in sensor housing1310) so that it is moved during a crash along with movement of thesensing mass 1341 (in the upward direction in FIG. 13) to thereby bringthe biasing spring contact 1301 into contact with contact 1302. Anelectrical circuit is hereby completed causing ignition of the primer orsquib and thereafter the igniter mix and propellant. As shown in FIG.13, the structure of the sensor housing 1310, inflator assembly 1312,mounting plate 1360 and sensing mass 1341 may be as described above inappropriate part.

FIG. 14 is a cross section view of a self-contained side impact airbagsystem using an electronic sensor that generates a signal representativeof the movement of a sensing mass. Unless otherwise stated orinconsistent with the following description of an airbag system with anelectronic sensor, the airbag system with an electronic sensor mayinclude the features of the airbag system described above and below. Anelectronic sensor is one in which the motion of the sensing mass istypically continuously monitored with the signal electronicallyamplified with the output fed into an electronic circuit which isusually a micro-processor. Electronic sensors typically useaccelerometers that usually make use of strain gage or piezo-electricelements shown here as 1401. The piezo-electric element generates asignal representative of the movement of the sensing mass. Modernaccelerometers are sometimes micro-machined and combined with otherelements on an electronic chip. In electromechanical sensors, the motionof the sensing mass is typically measured in millimeters and is muchlarger than the motion of the sensing mass in electronic sensors wherethe motion is frequently measured in microns or portions of a microns.The signal representative of the motion of the sensing mass is recordedover time and an algorithm in the micro-processor may be designed todetermine whether the movement over time of the sensing mass result in acalculated value which is in excess of the threshold value based on thesignal. The sensing mass may constitute part of the accelerometer, e.g.,the sensing mass is a micro-machined acceleration sensing mass. In thiscase, the microprocessor determines whether the movement of the sensingmass over time results in an algorithmic determined value that is inexcess of the threshold value based on the signal.

In embodiments using an electronic sensor, the inflator may include aprimer which is part of an electronic circuit including theaccelerometer such that upon movement over time of the sensing massresults in a calculated value in excess of the threshold value, theelectronic circuit is completed thereby causing ignition of the primer.

When the term electrical as used herein it is meant to include bothelectromechanical and electronic systems.

FIG. 15 is a schematic of the electric circuit of an electromechanicalor electronic self-contained side impact airbag system. Theself-contained module shown generally at 1500 contains a sensor assembly1540 and an airbag and inflator assembly 1510. The sensor assembly 1540contains a sensor 1541, a diagnostic module 1542, an energy storagecapacitor 1543, and a pair of diodes 1515 to prevent accidentaldischarge of the capacitor if a wire becomes shorted. The module iselectrically connected to a diagnostic monitoring circuit 1560 by wire1501 and to the vehicle battery by wire 1503. It is also connected tothe vehicle ground by wire 1502. The sensor, diagnostic and capacitorpower supplies are connected to the squib by wires 1505 through 1507.

In a basic configuration, the diagnostic monitoring circuit 1560 checksthat there is sufficient voltage on the capacitor to initiate theinflator in the event of an accident, for example, and either of wires1501, 1502, 1503 or 1504 are severed. In this case, the diagnosticinternal to the self-contained module would not be necessary. In moresophisticated cases, the diagnostic module 1542 could check that thesquib resistance was within tolerance, that the sensor calibration wascorrect (through self testing) and that the arming sensor has notinadvertently closed. It could also be used to record that the armingsensor, discriminating sensor and airbag deployment all occurred in theproper sequence and record this and other information for furtherinvestigative purposes. In the event of a malfunction, the diagnosticunit could send a signal to the monitoring circuitry that may be no morethan an indication that the capacitor was not at full charge.

A substantial improvement in the reliability of the system is achievedby placing the diagnostic module and backup power supply within the selfcontained airbag system particularly in the case of said impacts wherethe impact can take place at any location over a wide area. An impactinto a narrow pole at the hinge pillar, for example, might be sufficientto sever the wire from the airbag module to the vehicle power sourcebefore the sensor has detected the accident.

Most of the advantages of placing the sensor, diagnostic and backuppower supply within the self contained module can of course be obtainedif one or more of these components are placed in a second module inclose proximity to the self contained module. For the purposes ofelectromechanical or electronic self contained modules, therefore, asused herein, the terms “self contained module” or “self contained airbagsystem” will include those cases where one or more of the componentsincluding the sensor, diagnostic and backup power supply are separatefrom the airbag module but in close proximity to it. For example, in thecase of steering wheel mounted systems, the sensor and backup powersupply would be mounted on the steering wheel and in the case of sideimpact door mounted systems, they would be mounted within the door. Inconventional electrical or electronic systems, on the other hand, thesensor, diagnostic module and backup power supply are mounted remotefrom the airbag module in a convenient location typically centrally inthe passenger compartment such as on the tunnel, under the seat or inthe instrument panel.

With the placement of the backup power supplying in the self containedmodule, greater wiring freedom is permitted. For example, in some casesfor steering wheel mounted systems, the power can be obtained throughthe standard horn slip ring system eliminating the requirement of theribbon coil now used on all conventional driver airbag systems. For sideimpact installations, the power to charge the backup power supply couldcome from any convenient source such as the power window or door lockcircuits. The very low resistance and thus high quality circuits andconnectors now used in airbag systems are not required since even anintermittent or high resistance power source would be sufficient tocharge the capacitor and the existence of the charge is diagnosed asdescribed above.

Herein, the terms capacitor, power supply and backup power supply havebeen used interchangeably. Also, other energy storage devices such as arechargeable battery could be used instead of a capacitor. For thepurposes of this disclosure and the appended claims, therefore, the workcapacitor will be used to mean any device capable of storing electricalenergy for the purposes of supplying energy to initiate an inflator.Initiation of an inflator will mean any process by which the filling ofan airbag with gas is started. The inflator may be either purepyrotechnic, stored gas of hybrid or any other device which provides gasto inflate an airbag.

FIG. 16 is a side view showing the preferred mounting of two selfcontained airbag modules 1601 and 1602 on the side on a two doorvehicle. Module 1601 is mounted inside of a door, whereby the sensorhousing 101 of module 1601 is most proximate the exterior of thevehicle, while module 1602 is mounted between the inner and outer sidepanels at a location other than the door, in this case, to protect arear seated occupant. Each of the modules has its own sensor and, in thecase of electrical self-contained systems, its own capacitor powersupply and diagnostic circuit. Any of the airbag systems disclosedherein may be mounted either inside a door or between inner and outerside panels of the vehicle at a location other than the door. In view ofthe mounting of module 1602 between inner and outer panels of thevehicle at a location other than the door, the inner and outer panelsare thus fixed relative to the vehicle frame and the module 1602 is alsothus fixed relative to the frame. By contrast, the module 1601 mountedinside the door is moved whenever the door is opened or closed.

Although several preferred embodiments are illustrated and describedabove, there are possible combinations using other geometries, materialsand different dimensions for the components that can perform the samefunction. For example, the biasing spring need not be the same as thebiasing spring in the case of the implementation shown in FIG. 1 and amagnet might be used in place of a biasing spring for several of themechanical cases illustrated. Therefore, this invention is not limitedto the above embodiments and should be determined by the followingclaims.

1. A vehicle including a side impact airbag system, front wheels, rearwheels and a frame defining a front of the vehicle, a rear of thevehicle and first and second sides of the vehicle, said airbag systemcomprising: a system housing arranged on the first side of the vehiclealongside at least a portion of a passenger compartment of the vehicle,said system housing defining an interior space, at least one inflatableairbag arranged in said interior space of said system housing such thatwhen inflating, said at least one airbag is expelled from said systemhousing into the passenger compartment, inflator means arranged at leastpartially within said interior space of said system housing forinflating said at least one airbag, said inflator means comprising aninflator housing containing propellant, and a crash sensor forinitiating inflation of said at least one airbag via said inflator meansupon a determination of a crash requiring inflation of said at least oneairbag, said crash sensor comprising a sensor housing arranged withinsaid system housing, and a sensing mass arranged in said sensor housingto move relative to said sensor housing in response to accelerations ofsaid sensor housing resulting from the crash into the first side of thevehicle such that upon movement of said sensing mass in excess of athreshold value, said crash sensor initiates said inflator means toinflate said at least one airbag based on movement of said sensing mass.2. The vehicle of claim 1, wherein said crash sensor is an electronicsensor and the movement of said sensing mass is monitored.
 3. Thevehicle of claim 2, wherein said electronic sensor further comprisesgenerating means coupled to said sensing mass for generating a signalrepresentative of the movement of said sensing mass.
 4. The vehicle ofclaim 3, wherein said signal is monitored and recorded over time.
 5. Thevehicle of claim 3, wherein said electronic sensor further comprises amicro-processor and an algorithm for determining whether the movementover time of said sensing mass as processed by said algorithm results ina calculated value which is in excess of the a threshold value based onsaid signal.
 6. The vehicle of claim 3, wherein said generating meanscomprise at least one piezoelectric element.
 7. The vehicle of claim 1,wherein said crash sensor further comprises an accelerometer, saidsensing mass constituting part of said accelerometer.
 8. The vehicle ofclaim 7, wherein said crash sensor further comprises a micro-processorfor determining whether the movement of said sensing mass over timeresults in an algorithmic determined value which is in excess of the athreshold value based on said signal.
 9. The vehicle of claim 7, whereinsaid accelerometer includes a piezo-electric element for generating asignal representative of the movement of said sensing mass, said crashsensor further comprising a micro-processor for determining whether themovement of said sensing mass over time results in an algorithmicdetermined value which is in excess of the a threshold value based onsaid signal.
 10. The vehicle of claim 7, wherein said inflator meanscomprise a primer arranged in said inflator housing, said crash senorincluding an electronic circuit including said accelerometer and saidprimer such that upon movement over time of said sensing mass resultingin a calculated value in excess of the a threshold value, the electroniccircuit is completed thereby causing ignition of said primer.
 11. Thevehicle of claim 1, wherein said system housing comprises a mountingplate having a bottom wall and flanged side walls, said bottom wallhaving an aperture, said inflator housing being arranged in saidaperture.
 12. The vehicle of claim 1, wherein said sensor housing ismounted directly to said inflator housing.
 13. The vehicle of claim 1,wherein the first side of the vehicle has a door and said system housingis arranged inside said door.
 14. The vehicle of claim 1, wherein aportion of the first side of the vehicle has inner and outer panelsfixed in position relative to the frame, said system housing beingarranged between said inner and outer panels.
 15. The vehicle of claim1, further comprising a capacitor arranged within said system housing tosupply power to initiate deployment of said airbag system.
 16. Thevehicle of claim 1, further comprising an electronic diagnostic systemarranged within said system housing to permit diagnoses of a faultwithin said airbag system.
 17. The vehicle of claim 1, wherein saidsensor housing is exterior of said inflator housing.
 18. An Aself-contained airbag safety restraint system for a vehicle comprising:an inflatable airbag having an interior, an inflator assembly having aninflator housing, an ignitable gas generating material contained in saidinflator housing and at least one passage extending between said gasgenerating material and said interior of said airbag such that uponignition of said gas generating material, gas is generated and flowsthrough said at least one passage into said interior of said airbag toinflate said airbag, and an electronic crash sensor for causing ignitionof said gas generating material upon a determination of a crashrequiring inflation of said airbag, said crash sensor comprising asensor housing situated exterior of and mounted proximate to saidinflator housing, an accelerometer comprising a sensing mass arranged insaid sensor housing to move relative to said sensor housing in responseto accelerations of said sensor housing resulting from the crash, saidaccelerometer including a piezoelectric element for generating a signalrepresentative of the movement of said sensing mass, and amicro-processor comprising an algorithm for determining whether themovement of said sensing mass over time results in a calculated valuewhich is in excess of a threshold value based on the signal such that ifthe movement over time of said sen sing sensing mass results in acalculated value which is in excess of the threshold value, saidmicro-processor causes ignition of gas generating material and thusinflation of said airbag.
 19. The system of claim 18, wherein saidsensor housing is mounted proximate to said inflator housing.
 20. Thesystem of claim 18, wherein the sensing mass is a micro-machinedelement.
 21. The system of claim 18, wherein said inflator assemblyfurther comprises a primer arranged in said inflator housing forigniting said gas generating material, said crash sensor including anelectronic circuit including said accelerometer and said primer suchthat upon movement of said sensing mass over time resulting in acalculated value in excess of the threshold value, the electroniccircuit is completed thereby causing ignition of said primer.
 22. An Aself-contained airbag safety restraint system for a vehicle comprising:an inflatable airbag having an interior, an inflator assembly having aninflator housing, an ignitable gas generating material contained in saidinflator housing and at least one passage extending between said gasgenerating material and said interior of said airbag such that uponignition of said gas generating material, gas is generated and flowsthrough said at least one passage into said interior of said airbag toinflate said airbag, and an electronic crash sensor for causing ignitionof said gas generating material upon a determination of a crashrequiring inflation of said airbag, said crash sensor comprising asensor housing situated exterior of and mounted proximate to saidinflator housing, and an accelerometer arranged in said sensor housingand including a sensing mass movable relative to said sensor housing inresponse to accelerations of said sensor housing resulting from thecrash, said accelerometer being arranged to generate a signalrepresentative of the movement of said sensing mass over time, saidcrash sensor being arranged to cause ignition of said gas generatingmaterial if the movement over time of said sensing mass represented bysaid signal results in a calculated value which is in excess of athreshold value.
 23. The system of claim 22, wherein said sensor housingis mounted proximate to said inflator housing.
 24. The system of claim22, wherein said sensing mass is a micro-machined element.
 25. Thesystem of claim 22, wherein said inflator assembly further comprises aprimer arranged in said inflator housing for igniting said gasgenerating material, said crash sensor including an electronic circuitincluding said accelerometer and said primer such that upon movementover time of said sensing mass results in a calculated value in excessof the threshold value, the electronic circuit is completed therebycausing ignition of said primer.
 26. The system of claim 22, whereinsaid crash sensor further comprises a micro-processor for determiningwhether the movement over time of said sensing mass results in acalculated value which is in excess of the threshold value based on saidsignal.
 27. A vehicle including a side impact airbag system, frontwheels, rear wheels and a frame defining a front of the vehicle, a rearof the vehicle and first and second sides of the vehicle, said airbagsystem comprising: a system housing arranged on the first side of thevehicle alongside at least a portion of a passenger compartment of thevehicle, said system housing defining an interior space, at least oneinflatable airbag arranged in said interior space of said system housingsuch that when inflating, said at least one airbag is expelled from saidsystem housing into the passenger compartment, inflator means arrangedat least partially within said interior space of said system housing forinflating said at least one airbag, said inflator means comprising aninflator housing containing propellant, and a crash sensor forinitiating inflation of said at least one airbag via said inflator meansupon a determination of a crash requiring inflation of said at least oneairbag, said crash sensor comprising a sensor housing arranged proximateto said inflator housing, and a sensing mass arranged in said sensorhousing to move relative to said sensor housing in response toaccelerations of said sensor housing resulting from the crash into thefirst side of the vehicle such that upon movement of said sensing massin excess of a threshold value, said crash sensor initiates saidinflator means to inflate said at least one airbag.
 28. The vehicle ofclaim 27 wherein the threshold value is a maximum motion of said sensingmass required to determine that a crash requiring deployment of said atleast one airbag is taking place.
 29. The vehicle of claim 1, whereinsaid crash sensor initiates said inflator means to inflate said at leastone airbag based on movement of said sensing mass in excess of athreshold value.